Process for the loosening of dead hairs in fur pelts

ABSTRACT

UNIFORMLY LOOSENING DEAD HAIRS IN FUR PELTS WITHOUT LOOSENING THE SHORT HAIRS OF THE UNDERFUR BY TREATING THE SOAKED PELTS WITH A PROTEOLYTIC ENZYME AT A WEAKLY ACID TO WEAKLY ALKALINE PH UNTIL THE DEAD HAIRS ARE LOOSENED BUT BEFORE THE SHORT HAIRS ARE LOOSENED.

United States Patent 013cc 3,558,430 PROCESS FOR THE LOOSENING OF DEAD HAIRS IN FUR PELTS Rolf Monsheimer, Darmstadt-Eberstadt, and Ernst Pfleiderer, Darmstadt-Arheilgen, Germany, assignors to Rohm & Haas G.m.b.H., Darmstadt, Germany No Drawing. Filed Feb. 27, 1968, Ser. No. 708,536 Claims priority, application Germany, Mar. 3, 1967, R 45,420 Int. Cl. C1211 1/00 US. Cl. 1956 7 Claims ABSTRACT OF THE DISCLOSURE Uniformly loosening dead hairs in fur pelts without loosening the short hairs of the underfur by treating the soaked pelts with a proteolytic enzyme at a weakly acid to weakly alkaline pH until the dead hairs are loosened but before the short hairs are loosened.

The present invention relates to processes for the loosening of dead hairs in fur pelts to facilitate their removal therefrom.

The loosening and removal of coarse, long, dead hairs or bristles from fur pelts, mostly from furs such as nutria, beaver, muskrat, and seal, results in a considerable improvement in the quality of the fur. In known processes for such removal, the dead hairs are mechanically plucked, optionally after a sweating process, or that part of the hairs which projects beyond the short hairs of the underfur is cut off.

The process of mechanical plucking has the disadvantage that the dead hairs are broken off by the process, leaving a residue. Shearing involves the same disadvantage. Since the dead hairs behave differently from the underfur on dyeing during later finishing, only a limited improvement in quality can be achieved using these removal processes.

In the prior art, sweating processes are used as an adjunct to soaking, as known in the art of dewooling sheepskins. Dead hairs are loosened by such a process, and then are manualy plucked. However, the time required for loosening of the hairs is not definite. It .is not possible to remove such hairs from the entire surface of a skin in one step using a sweating process. Rather, it is usually necessary to pluck as many hairs as possible after a certain treatment time and then to return the pelt back to the sweating chamber. The uncontrollable conditions of this process not only loosen the dead hairs, but also loosen the short hairs of the underfur, giving rise to possible bare patches.

According to the present invention a process avoiding the disadvantages of the prior art has been found for the loosening of dead hairs in fur pelts. According to the new process, the dead hairs are so uniformly loosened over the entire skin in a short period of time that they can be plucked in a single process step. The hairs to be removed are not broken off by this treatment, so that a completely uniform pelt is obtained after coloring.

According to the present invention, a fur pelt is treated with a proteolytic enzyme in a weakly acid to weakly alkaline medium, i.e. at a pH of about 6 to about 9, until a uniform loosening of the dead hairs occurs. At pH values below about 6, the desired effect is no longer observed or is only observed after unfeasibly long treatment times.

In most cases, loosening generally requires enzyme treatment over a period of from two to six hours at a temperature from about 15 C. to about 50 C., preferably from about 20 C. to about 40 C., with shorter Patented Jan. 26, 1971 treatment times being chosen at higher temperatures.

The enzyme can be employed in a liquid phase, in which case it is advantageously added to the soaking bath for the pelts. After soaking for about three to five hours, the skins are hung flesh side to flesh side for an additional one or two hours at a temperature of about 30 C. to 40 C. in air having a relative humidity of from 70-80 percent.

The enzyme can also be applied in powder or paste form to the fiesh side of soaked raw pelts prior to hanging. As soon as the coarse hairs are uniformly loosened, they are plucked out. It is recommended that the removal of dead hairs be terminated before further action of the enzymes beings a loosening of the short hairs of the underfur in the flanks. Up to this point, the fastness of the underfur is not yet affected.

After removal of the dead hairs, the enzymes should be inactivated as soon as possible. This can be done, for example, by treatment with formaldehyde or by the usual dressing steps.

The proteolytic enzymes already known in the leather industry are employed in the present invention. Bacterial proteases, mold fungus proteases, pancreatic enzymes, or combinations of these materials, are preferably used in the process of the invention. The proteolytic enzymes obtained from cultures of Aspergilli such as Aspergillus niger, Aspergillus oryzae, or Aspergillus flavus, or from cultures of Streptomyces sp. or Clostridium acetobutylz'cumr, can be named as exemplary. Among the bacterial proteases, those of Bacillus subtilis and Bacillus mesentericus have proved good in the process of the invention. Trypsin, papain, and pepsin are also suitable enzymes.

Enzymes having a proteolytic activity corresponding with an enzyme value of about 8000-12000 are suitably used in an amount of from about 0.1 percent to about 2 percent, preferably from about 0.4 percent to 1 percent, by weight of the pelts treated.

For materials which are rich in natural fat it is desirable to employ non-ionic wetting agents, for example those comprising glycol ethers, in the enzyme treatment.

A better understanding of the present invention and of its many advantages will be had by referring to the following specific examples given by way of illustration.

EXAMPLE 1 Dried nutria pelts were covered with 8 to 10 times their weight of water. Four to five percent, by weight of the pelts, of bacterial protease having an enzyme strength of 9000 and derived from Bacillus subtilis were added per liter of bath. The pelts were kept in the bath for one to two hours, then were hung flesh side to flesh side in a room at a temperature of from 30 C. to 40 C. and at a relative humidity of from 70-80 percent. After one to two hours the guard hairs could be plucked.

EXAMPLE 2 Dried muskrat pelts were covered with water at 20 C. in a weight ratio of 1:8 to 1:10. Four to five percent, by weight of the pelts, of bacterial protease like that used in Example 1 were added to the bath with from 0.8 to 1 percent of polyglycol ether. The treatment time was from three to four hours, after which the skins were hung and plucked as in Example 1.

EXAMPLE 3 Dried nutria pelts were covered with water at 20 C. in a weight ratio of 1:8 to 1:10. Four to five precent, by weight of the pelts, of mold fungus tryptase derived from Aspergillus oryzae and having an enzyme strength of 10000 were added to the bath. The skins were kept in the bath for two to three hours, then further treated as in Example 1.

EXAMPLE 4 Dried nutria skins were covered with water at 20 C. in a weight ratio of 1:8 to 1:10. l.62 percent of bacterial protease derived from Bacillus subtilis, 3.2-4 percent of fungus tryptase derived from Aspergillus flavus, and 0.8l percent of polyglycol ether, all percentages being by weight of the skins, were added to the bath. The skins were kept in the bath for from four to five hours and then were further treated as in Example 1.

What is claimed is:

1. A process for the treatment of fur pelts to loosen dead hairs selectively and uniformly, Without loosening of the underfur, to render said dead hairs removable from said pelts, which process comprises contacting soaked pelts at a weakly acid to weakly alkaline pH with a proteolytic enzyme until said dead hairs are loosened but before the short hairs of the underfur are loosened.

2. A process as in claim 1 wherein raw pelts are contacted with said proteolytic enzyme in a soaking bath.

3. A process as in claim 2 wherein said soaking bath additionally comprises a non-ionic wetting agent.

4. A process as in claim 1 wherein the flesh side of soaked raw pelts is contacted with an enzyme in solid form.

5. A process as in claim 4 wherein said solid enzyme is a paste or powder.

6. A process for the treatment of fur pelts to loosen dead hairs collectively and uniformly, without loosening of the underfur, to render said dead hairs removable from said pelts, which process comprises contacting soaked pelts at a pH from 6 to 9 at a temperature from about 15 C. to about 50 C. for from 2 to 6 hours until said dead hairs are loosened but before the short hairs of the underfur are loosened.

7. A process as in claim 6 wherein said enzyme is used in an amount equivalent to 0.1 to 2 percent, by weight of the pelts treated, of an enzyme having an enzyme value of 8,000l2,000.

References Cited Grimm, 0.: Chemical Abstracts, vol. 54, No. 168896, 1960.

A. LOUIS MONACELL, Primary Examiner G. M. NATH, Assistant Examiner 

